The plug wires carry a very tiny amount of current under extremely high voltage. The conductors inside must offer some resistance to flow of current, or operation of a radio in the car, or even nearby, would be impossible. For these reasons, these wires deteriorate steadily and often produce puzzling and unexpected lapses in performance. The most typical evidence of wire problems is the sudden failure of the car to start on a damp morning.
The wires should be inspected frequently for full seating at the plugs and distributor cap towers. Before inspection, wipe the wires carefully with a cloth slightly moistened with a non-flammable solvent so it will be easier to see cracks or other damage. The insulation and all rubber boots should be flexible and free of cracks. Replace the wires as a set as soon as any such problems develop.
Unfortunately, the invisible conductors inside high quality wires can deteriorate before evidence of poor insulation exists. You can remove such wires and test the resistance if you have an ohmmeter. Measure the length of each wire with a ruler and then multiply the length by the figures given, in order to measure total resistance. Resistance must be 250-600 ohms per inch (25mm) for 1981-90 vehicles and to 250-1000 ohms per inch (25mm) for 1991-95 models, or to 3,000-7,200 ohms per foot (30.5 cm) for 1981-90 models and to 3,000-12,000 ohms per foot (30.5 cm) for 1991-95 models. If you wish to check the cap at the same time, you can run your test between the spark plug end of the plug wire and the contact at the center of the inside of the cap.
If you do not have an ohmmeter, you may want to take you car to a mechanic or diagnostic center with an oscilloscope type of diagnosis system. This unit will read the curve of ignition voltage and uncover problems with wires, or any other component, easily. You may also want to refer to the previous procedures on spark plug analysis, as looking at the plugs may help you to identify wire problems.
REMOVAL & INSTALLATION
See Figure 1
- If applicable, remove the 2 distributor cover mounting bolts and the distributor cover.
- Label and remove the ignition coil cable from the ignition coil center tower. Although on most vehicles the ignition coil cable does not utilize a positive-locking terminal, on the Premier models it does.
- Label and remove all of the spark plug cable ends from the spark plugs.
- Note the spark plug cable routing, then detach the cables from any retainers or brackets.
- Matchmark the cap to the distributor housing. Remove the distributor cap from the distributor housing by unscrewing the cap hold-down screws. Lift the cap off of the housing with the spark plug cables attached.
- From inside of the distributor cap, use a pair of pliers to compress the positive-locking terminal tangs of the spark plug wires. While the tangs are compressed, pull the cable out of the ddistributor cap from the outside.
- Push the spark plug cable terminals into the distributor cap until the positive-locking terminal tangs are fully engaged.
- Install the distributor cap with the matchmarks aligned, then install the distributor cap hold-down screws until snug.
- Route the spark plug cables as when removed into any retainers or brackets. Push the spark plug cables onto the spark plugs until fully seated.
- Install the ignition coil cable so that the end is fully inserted into the ignition coil tower.
- If necessary, install the distributor cover.